With the continued advancement of medical technology and of portable electronics and mechanics, handheld diagnostic equipment for a multitude of types of tests on biological samples has become available.
Laboratory tests on biological samples have traditionally been performed for diagnosis, screening, disease staging, forensic analysis, pregnancy testing, drug testing, and other reasons. While a few qualitative tests, such as pregnancy tests, have been reduced to simple kits for the patient's home use, a large number of quantitative tests still require elaborate procedures that often necessitate the expertise of trained technicians in a laboratory setting using sophisticated instruments. In recent years, some of these tests have been made available to medical practitioners and the like for in situ analysis by using handheld testing devices that embody sensors and computational electronics for sample analysis, and mechanical actuation assemblies for manual and/or automated sample and testing fluid manipulation. Such handheld testing devices provide the advantage of being able to perform analysis and testing at the point of care for immediate results that could improve diagnostic timeliness and accuracy.
U.S. Pat. No. 6,222,371 by Snyder, for example, describes a handheld boiler and coolant fluid testing apparatus with test fluid reservoirs in the testing apparatus for receiving fluids to be tested. The described apparatus includes a main fluid reservoir and an overflow reservoir, with means for controlling fluid levels for improved testing accuracy and consistency.
For testing of biological samples, testing devices with disposable sample repositories have been used. U.S. Pat. No. 4,929,426 by Bodai et al., U.S. Pat. No. 4,994,167 by Shults et al., and U.S. Pat. No. 5,405,510 by Betts et al. describe portable biological fluid measuring devices with detachable and disposable sample cartridges. Bodai et al. describe a pH testing apparatus that houses internal blood sample holding cartridges for receiving blood samples deposited into the apparatus using a syringe. Shults et al. describe a testing device with a detachable cartridge that includes a membrane for receiving a fluid sample, the membrane being maintained in contact with electrodes of the testing device for testing the fluid sample. Betts et al. describe an analyte measuring device with a mated disposable cartridge that includes an inlet for introduction of fluids, sensors for performing the tests, and an electronic connection for providing testing controls and for communicating results to the measuring device.
Additionally, single use discrete sample carriers, and corresponding testing devices, have been developed for separate sample collection and for providing a simple interface to present collected samples to the testing device.
U.S. Pat. No. 5,037,614 by Makita et al., U.S. Pat. No. 5,316,727 by Suzuki et al., and U.S. Pat. No. 7,547,557 by LaBorde et al. describe discrete sample carriers for collecting test samples and presenting the collected samples to a corresponding testing device. Makita et al. describe using a test paper stick for collecting a blood sample, and inserting the test paper stick into an opening of a testing device for performing optical tests on the blood sample collected on the test paper. Suzuki et al. describe an enclosed test piece internally embodying the test paper, the test piece having an opening for collecting a blood sample onto the test paper and another opening for allowing optical testing when inserted in a corresponding testing device. LaBorde et al. describe a sample carrier embodying a sample receiving port and flow structure from the receiving port to an open test strip for allowing testing by a magnetic reader device.
Correspondingly, U.S. Pat. No. 5,096,669 by Lauks et al. describes a handheld sensing device for measuring analytes in a blood sample. Other handheld devices are described in U.S. Pat. No. 5,873,990 by Wojciechowski et al., U.S. Pat. No. 7,041,206 by Gephart et al. Lauks et al., Wojiechowski et al., and Gephart et al. describe single use test cartridges as fluid sample carriers for insertion into a handheld test apparatus for performing different types of tests on the fluid samples. In particular, Lauks et al. describe an apparatus and cartridge system commercially known as the i-STAT® point-of-care blood testing system, which uses disposable cartridges with sensors for performing one or more blood tests. These cartridges are operated using a portable analyzer which has a display for providing test results and other information to the user. The i-STAT® system is described in detail by the i-STAT® System Manual (2010) (Abbott Point of Care Inc., Princeton, N.J.), which is incorporated here in its entirety.
U.S. Pat. No. 7,419,821 by Davis et al. describes in detail a sample-carrying cartridge used for the i-STAT® system. Such cartridges include an inlet for receiving a sample, separate repositories for the sample and a testing liquid, and channeling mechanisms for mixing the liquids. The apparatus for use with this cartridge includes a mechanical actuator that triggers the mixing by applying mechanical force to an appropriate portion of the test cartridge.
With the continued advancement of cartridge design for accommodating increasingly sophisticated tests, there has been a need for parallel advancement in reading devices for actuating increasingly complex testing cartridges. To meet the needs for such tests, sensor and computational electronics and mechanical actuation elements have needed to become more elaborate.